Java this and super Keywords: 17 MCQs

Q1. Which statement best describes the difference between `this` and `super`?

Q2. Inside which of the following can `this` legally appear?

Q3. What does the statement `this.name = name;` do inside a constructor?

Q4. What is the required position of a `this(...)` constructor call within a constructor?

Q5. Which of these is a valid use of `this`?

Q6. Which statement about `this` and `super` is TRUE?

Q7. Every constructor that does not explicitly call `this(...)` or `super(...)` receives an implicit `super()` call as its first statement, which is why a subclass fails to compile when the parent lacks a no-arg constructor.

Q8. A `Student` class has field `name` and a constructor parameter also called `name`. The constructor body is just `name = name;`. What is the field's value after construction?

Q9. A subclass constructor writes neither `this(...)` nor `super(...)`. What does the compiler do?

Q10. `Animal.speak()` returns `"..."`. `Dog` overrides `speak()` as `return super.speak() + " Woof";`. What does `new Dog().speak()` return?

Q11. A class has constructors `Point()` and `Point(int x, int y)`. Which body correctly chains `Point()` to the two-arg constructor?

Q12. In a subclass, `super.field` is used to access what?

Q13. The parent class `Animal` defines only `Animal(int age)`. A subclass `Dog` has a constructor with no explicit `super(...)` or `this(...)`. What happens?

Q14. Why does `super.super.method()` fail to compile?

Q15. Which pair of statements about `this(...)` and `super(...)` is correct?

Q16. A developer overrides `equals` in a class and writes `return this.id == other.id;`. What role does `this` play here?

Q17. Consider the following class definitions: ```java class Parent { Parent(int x) { } } class Child extends Parent { Child() { this(5); } Child(int x) { super(x); } } ``` What happens when you try to instantiate `Child` using `new Child();`?